Proper power-up sequencing is an ever-present problem with computers and complex systems. If subordinate systems are energized before controller systems the unsupervised subordinate systems may respond to false signals and injure themselves or other components or cause control loop errors or even endanger personnel. In autonomous mobile robots, if the drive motor amplifier is energized before the motor controller, the drive motor amplifier will not be supervised and may see noise which it interprets as a drive command. The robot may as a result dash off at high speed, in any direction, completely uncontrolled. The steering motor for the wheels must be under control before the drive motor can be activated or a moving robot without steering will be loosed. With certain amplifiers the bias must arrive close to the power or the amplifier may destroy itself. If subordinate systems power-up before control systems, then the subordinate systems may be actively, wastefully, dangerously executing false commands. Servo-control loop errors can lock up the robot when it tries to achieve unrealistic goals set by the false commands, to the extent that the robot shuts down and skilled personnel have to become involved to remedy the situation.
One approach to the problem is to simply build time delays into each different piece of equipment so that each turns on at a predetermined time. One problem with this approach is that the arrival of the time gate for turning on any particular component does not assure that previous windows arrived on time and that power was indeed supplied to the attendant equipment.